Alcator C-Mod Weekly Highlights February 5, 2007 Physics ------- A novel Alpha Radioisotope Remote Ion Beam Analysis (ARRIBA) diagnostic is being designed to measure erosion, deposition, and hydrogenic retention at high heat flux surfaces within a fusion device. ARRIBA utilizes a Cm-244 radioisotope to perform in situ analysis of plasma exposed surfaces. Material surfaces are rotated between exposure and analysis positions by an innovative J x B activated mechanical assembly. This work is being done by graduate student Soren Harrison, U. Wisconsin, and Dennis Whyte, with possible applications to C-Mod being considered. Operations ---------- We began work with GE last week to coordinate primary breakers for operation with the higher pulsed power demands expected from the lower hybrid and ICRF systems during the next run campaign. Two new projectors were installed in the control room to replace the functionality of the large mimic panel at the front of the room. There are now three screens; one is currently configured for engineering data, and the other two for physics data. All outside work on the liquid nitrogen (LN2) feedline has been completed. All joints were silver soldered and successfully pressure tested at 100 psi. Cryopump -------- Work continued last week on the new PLC/PC control system for the cryopump. Installation of the cryopump LN2 exhaust line into the LN2 sump has begun. The transfer lines needed to feed LN2 to the cryopump are now in-house. Lower Hybrid System ------------------- Fabrication in-house of high power dummy loads was begun last week. Extensive modeling indicates that these units will be superior to available commercial units. These loads are needed to speed up the phase and amplitude calibration process. We also continued preparations for the calibrations by running 0.4 s pulses at up to 200 kW per klystron during which the phase and amplitude of the power were continuously scanned (rasterized).Ron Parker and Jim Terry visited GA last week for the meeting of the DIII-D Program Advisory Committee. They are both members of the PAC, which is chaired by Parker. Miklos Porkolab also traveled to GA to participate in the meeting. ICRF Systems ------------ All antenna vacuum flanges are now leak-tight, and re-assembly of the antennas continued in-vessel. Work on re-assembly of the #2 fast ferrite tuner module continued last week with installation of the new support bars. Installation of the ferrite loaded center conductor into the magnet assembly should proceed this week. Work on crowbar #3 was completed last week, and work on crowbar #4 will continue this week. Diagnostics ----------- All studs and brackets have been installed for the F- and G-Port CXRS periscopes and calibrations are underway. Tiles needed to protect the polarimeter shutter assembly have been bevelled and are ready to be baked. A first electro-formed retro-reflector was received last week with several more expected in-house this week. All 2-D bolometer box components are in-house and studs have been shot between A- and K-Port for three out of four of the boxes. Positioning of the fourth box is being determined. A trial installation of the bolometer box at K-Port has been completed. A slight modification to the box brackets is needed. Data acquisition modules used for neutron detectors have been refurbished and brought back on-line in preparation for the next run campaign. The focus of one of the Charge Exchange Recombination Spectroscopy (CXRS) detector/spectrometers was checked with a neon spectrum and found to be satisfactory. The system had been focused last week using a helium lamp. The analysis of the focusing data set and the initial instrument function data set was completed. The toroidal CXRS optics for r/a < 1 were installed, and the spatial and intensity calibrations completed. The poloidal CXRS optics for r/a<1 were installed and spatially calibrated. Spatial positions for the Beam Emission Spectroscopy (BES) discrete fiber bundles and for a new 6X6 array were selected; the fibers were installed, and the spatial calibration was accomplished via back-lighting. Four of the fibers will add additional poloidal coverage at R=87.5 cm to the coverage provided by the 6X6 array. Other discrete bundles are placed at R ~ 70, 76.5 and 82.5 cm. The discrete bundles at R=87.5 cm were absolutely calibrated in case measurements of the beam profile are needed and to estimate the beam density at the plasma edge. The MDSPlus tree nodes were modified to allow more general description of the BES fibers which is needed with the addition of the 6X6 array. The setup of the electronics for the FRCECE diagnostic has been completed. Perry Phillips, UTexas, will return to MIT after pump-down to complete installation of the FRCECE waveguide. Alignment and calibration work on the MSE and CRXS systems continued over the weekend. Long Pulse Diagnostic Neutral Beam ---------------------------------- The DNB high voltage transformer was vacuum pumped, backfilled with SF6 gas, and successfully hi-potted to 55kV. The transformer was moved back to the C-Mod Cell and has been re-installed. The high voltage power supply has also been successfully hi-potted and brought back into operation for 30 ms pulses. All of the inverter currents were monitored and all were in spec and nearly identical in shape and magnitude. This result is a good indication that all eight transformers and rectifiers inside the transformer housing are working properly. Travel and Visits ----------------- VISIT OF THE U.S. GOVERNMENT ACCOUNTABILITY OFFICE (GAO) --- The GAO has been asked by Congress to study the role of the major domestic fusion facilities in support of ITER and to evaluate opportunities to leverage National Nuclear Security Administration investments for Inertial Fusion. Last Friday three representatives of the Office visited MIT: Mr. Edwin Woodward (Assistant Director), Mr. Leland Cogliani (Senior Analyst), and Mr. Christopher Banks (Analyst). Miklos Porkolab gave a presentation on fusion physics and engineering research at the PSFC. Earl Marmar presented a primer on fusion energy, and discussed the C-Mod program, including contributions to the ITER effort. He also addressed specific topics that were requested by the GAO representatives, and led a tour of the C-Mod facility. Presentations were also given by Joel Schultz on magnet technology, and Rick Temkin on gyrotron technology. The meeting included a round-table discussion of various issues related to fusion research. PSFC participants were Miklos Porkolab, Peter Catto, Jeff Freidberg, Martin Greenwald, Amanda Hubbard, Ian Hutchinson, Jim Irby, Bruce Lipschultz, Earl Marmar, Joel Schultz, Rick Temkin, Dennis Whyte, Steve Wolfe, and Steve Wukitch. Ron Bravenec, UTexas, was here last week working on the BES system. Ron Parker and Jim Terry visited GA last week for the meeting of the DIII-D Program Advisory Committee (PAC). They are both members of the PAC, which is chaired by Parker. Miklos Porkolab also traveled to GA to participate in the meeting. _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly